Underwater methane gas plumes, Photo: NOAA Okeanos Explorer Program, 2013
Over the past year, the climate risks of methane (CH4) released from natural sources have attracted increasing media attention in scientific and media forums as “the Arctic climate threat that nobody’s even talking about yet.”1)Mooney C (2015) The Arctic climate threat that nobody’s even talking about yet. Washington Post, 1 April, www.washingtonpost.com/news/energy-environment/wp/2015/04/01/the-arctic-climate-threat-that-nobodys-even-talking-about-yet/. Accessed 16 March 2016 Scientific journals have likewise run articles detailing the risks that methane, in addition to CO2, poses to atmospheric climate change, following scientific research indicating the “2 degree Celsius” limit of climate talks may be physically impossible.2)Knutti R et al (2016) A scientific critique of the two-degree climate change target. Nature Geoscience 9(1): 13-18. Methane therefore serves as something of an environmental “wildcard” in climate change risk assessments, posing the specter of abrupt environmental changes that move climate negotiations from diplomatic to security terms. And yet, despite the acute need to discuss methane as a security risk, such assessments have been sporadic, or not widely publicized due to the nature of the agencies conducting the assessments.
Most climate negotiations and media attention are focused on carbon dioxide (CO2), though this is only one of several important greenhouse gases in the atmosphere. Methane concentrations in the atmosphere have risen from pre-industrial levels of 715 parts per billion (ppb) to 1840 ppb in 2015, a result of agricultural, industrial, refuse and energy actions by humans over the past hundred or so years. While methane eventually breaks down into CO2 during its 15-year life cycle in the atmosphere, it is roughly 25 times more powerful as a greenhouse gas than CO2, making it a potent climate amplifier and an important factor in global climate negotiations and mitigation efforts.3)Gernaat D et al (2015) Understanding the contribution of non-carbon dioxide gases in deep mitigation scenarios. Global Environmental Change 33: 142-153.
The most worrying risks come from substances known as methane clathrates (or hydrates), highly fragile ice-lattice formations that are created under specific combinations of pressure and temperature. Immense reserves of methane exist in clathrate formations on continental seabeds, and there are questions about the role clathrates play in past climate changes, or what they may portend for the future.4)Mao W et al (2007) Clathrate hydrates under pressure. Physics Today 60(1): 42-47. Given certain changes to sea temperature and/or pressure, gigatons of methane could be released in sudden bursts from these crystalline sources, undercutting human efforts to slow greenhouse gas emissions and possibly sparking abrupt climate changes.
Assessing impacts of methane releases goes beyond consideration of meeting 2°C temperature targets at the United Nations Framework Convention on Climate Change (UNFCCC) negotiations, and should be increasingly framed as abrupt climate changes and impacts.5)Duarte, CM, Lenton, TM, Wadhams, P & Wassmann, P (2012) Abrupt climate change in the Arctic. Nature Climate Change 2(2): 60-62. Rather than the gradual and linear changes to air temperature that are often discussed, methane release poses the risk of sudden climatic changes and runaway greenhouse gas emissions, as warming temperatures release ever more CH4.
The project teams detailed to assess abrupt climate change at the US Department of Energy (DOE), and subsequently at the US Air Force (USAF), were concerned that climate ‘forcings’ such as methane could overwhelm critical vulnerabilities in vital systems, be they ecosystems, food production, transport and infrastructure, or social systems. Some academic climate security discussions focused on violent conflict, especially in less developed countries, hypothesizing that changes to environmental conditions or resource stocks would incite violence, and security risks would therefore be judged according to this increased risk of interstate conflict or civil war.6)Busby J et al (2013) Climate change and insecurity. International Security 37(4): 132-172. The DOE/USAF approaches, in contrast, used a human security lens, which assessed how sudden shocks from environmental factors could undermine systemic stability. The security community risk assessments were concerned with scenarios of climate disruption that included climate change-related disasters events that have already grown more common and require military responses even if no violence is involved (e.g. Hurricane Sandy in 2012).7)Briggs C (2012) Climate security, risk assessment and military planning. International Affairs 88(5): 1049-1064.
In developing scenarios to assess climate vulnerabilities, the Department of Energy and Department of Defense approaches relied upon scientific expertise, but security planners moved well beyond what was already well known or considered ‘most probable’ in terms of risk. The standard scientific approach to methane influences on climate change rely upon peer-reviewed studies that require 95% certainty of conclusions, which lends a form of conservatism to predictions of future conditions. Changing boundary conditions undermine certainty, like trying to predict how fast a car is driving while it slides sideways on ice. Yet as retired flag officers mentioned in the 2007 CNA Corporation report on climate security, in military terms, waiting for full information and certainty means waiting too long.8)CNA Military Advisory Board (2007) National Security and the Threat of Climate Change. Alexandria, VA: CNA. Planning scenarios also tend to work best when combining factors (rather than examining only one variable, such as daytime air temperature), as most disasters are improbable combinations of probable factors, thus eluding plans for ‘most likely’ events. Rather than rely upon historically-based risks, security planners more often find it useful to explore probabilistic “long tails,” where potential impacts are catastrophic and probabilities largely unknown due to shifting boundary conditions.9)Eddy C & Sase E (2015) Implications of the Fukushima nuclear disaster: Man-made hazards, vulnerability factors, and risk to environmental health. Journal of Environmental Health 78(1): 26-32.
Consequently, organizations such as the US Department of Defense focused less on the carbon emission and control regimes of the UNFCCC in the run-up to Paris, and more on the unexpected pathways where human and military security may be impacted. While the political questions concerning greenhouse gas mitigation are beyond the authority of militaries and intelligence agencies, the potential impacts and responses remain very much their responsibilities. The security risk assessments require examining where climate change may trigger change in vulnerable geologic systems, and how those abrupt changes create cascading impacts in ecological and human-related vulnerabilities. Vulnerabilities can then be made more resilient in advance of abrupt climate changes, while at the same time planning for appropriate disaster responses can occur. Methane has been a key concern since 2009 within this community, largely owing to the fragile nature of methane deposits, the multiple pathways for release and feedback effects, and the potentially catastrophic impacts should large-scale releases occur.
Often these large-scale release discussions have focused on the potential for methane release from terrestrial sources, a positive feedback loop where increased warming in regions like the Arctic can lead to the release of carbon from permafrost or peat bogs, which in turn results in even more warming. Some scientific studies have suggested that methane from permafrost thaw may be a long-term concern, but will not result in any abrupt ‘shock’ of greenhouse gases in the near future.10)Schuur E et al (2015) Climate change and the permafrost carbon feedback. Nature 520: 171-179.
Yet other risks still exist, ones that have not yet been fully studied, and may not be understood until their impacts are felt. The DOE began exploring potential scenarios for abrupt methane shocks in 2008, after initial reports from a Swedish-Russian research team that unexpected sources of methane were discovered emanating from underneath the Barents Sea. The US Navy began similar investigations in 2010, reporting to then Chief of Naval Operations Admiral Roughead on potential security impacts. Both the DOE and the US Navy were concerned over methane clathrate releases from marine sources, where total carbon reserves could total roughly 1 million cubic miles. Until 2008, it was widely believed that global warming would not significantly affect intermediate-depth water (or Arctic Intermediate Water (AIW)) where most clathrate deposits existed. With emerging reports that water may be warming at increasing depths, concerns arose that clathrate deposits would destabilize and release massive amounts of methane and carbon.11)Phrampus B & Hornbach M (2012) Recent changes to the Gulf Stream causing widespread gas hydrate destabilization. Nature 490: 527-530.
The DOE effort drew up initial scenarios for over-the-horizon methane releases in 2009, posing questions of what happens should clathrate deposits destabilize, and how these deposits would react to emerging technology allowing marine mining of this methane. The scenario identified Japan as a potential hotspot for this emerging risk or opportunity, due to geographic locations of clathrate deposits, relative lack of domestic energy sources, and the existence of a joint US-Japanese technology program for clathrate mining. The Fukushima disaster of 2011 accelerated concern over the scenario, as it brought together several necessary conditions for the scenario to become reality, including a country that:
- possesses commercial technology to mine methane clathrates;
- suffers a sudden energy shock requiring access to natural gas;
- and accompanied by evidence suggesting that the clathrates may destabilize anyway, giving mining efforts carte blanche for their efforts.
In 2011, the USAF Minerva Initiative created a follow-on planning scenario based upon the prehistoric Storegga Slide, where destabilization of methane clathrates on the Norwegian continental shelf triggered a massive tsunami that hit Scotland. USAF and NASA researchers drew up rough calculations showing that melting Arctic ice could theoretically trigger landslides and related detonation of subsea methane deposits, disaster events that would have large-scale security consequences. Subsequent work in 2014 by GlobalINT (which also led the USAF project) uncovered emerging (yet unpublished) research that marine clathrate deposits may also be destabilized not only by ocean temperatures, but by shifting pressure from rising sea levels. Although further research is needed, preliminary models indicate that as little as 20 cm rise in sea levels could trigger large-scale releases of methane from such deposits, sea levels that will easily be reached later this century.
The scenarios were not definitive, but they highlighted several key issues for discussing the role of methane in climate assessments:
- No single or easily predictable mechanisms exist for releasing methane. Assuming that only one pathway (e.g. global temperature change) contributes to risks tends to underestimate potential problems from technology or seemingly unrelated geologic shifts (e.g. sea level rise).
- Assessing impacts also requires going beyond linear pathways. Although methane’s contribution to the global greenhouse gas budget is crucial, cascading impacts on related systems must also be addressed to identify feedback loops and geographically specific risks. In other words, it’s complicated.
- Significant gaps exist between scientific, policy and security fields. While scientists tend to be methodologically conservative in making predictions, policymakers will often wait for full certainty before acting. Yet tipping points in complex systems are rarely known in advance, and never with certainty. Security planners understand this need to embrace uncertainty and to use risk assessment approaches, but security/intelligence and academic communities have rarely engaged one another systematically on such topics. Security rules for secrecy and academic rules for publishing are among the more obvious barriers to cooperation.
- Ultimately, this cooperation is crucial for understanding methane’s role in climate changes. Scientists possess enormous amounts of information that go beyond what appears in the published literature, particularly the nature of uncertainty surrounding their work (i.e. why don’t we know certain things, or what is known but still uncertain?). Intelligence and security experts, assuming they work in unclassified spaces, can help translate such data for policymakers in terms of specific risks, impacts, and preventative and mitigative measures. The following steps could be taken concerning methane risks:
- Provide a neutral forum for scientific-security-policy cooperation to include agencies such as DOD, European ministries of defense, the American Geophysical Union (AGU), NASA, etc. to implement scenario methodologies already developed for assessing abrupt climate change risks.
- Provide funding for academic research groups to contribute to efforts by programs such as the US Global Change Research Program (USGCRP), to take advantage of emerging research and data, and translate for policymakers.
- Effective methane-release scenarios can provide early warning clues for policymakers and media to understand unfolding events. They can provide a framework for connecting otherwise disparate news items and pieces of research.
References [ + ]
|1.||↑||Mooney C (2015) The Arctic climate threat that nobody’s even talking about yet. Washington Post, 1 April, www.washingtonpost.com/news/energy-environment/wp/2015/04/01/the-arctic-climate-threat-that-nobodys-even-talking-about-yet/. Accessed 16 March 2016|
|2.||↑||Knutti R et al (2016) A scientific critique of the two-degree climate change target. Nature Geoscience 9(1): 13-18.|
|3.||↑||Gernaat D et al (2015) Understanding the contribution of non-carbon dioxide gases in deep mitigation scenarios. Global Environmental Change 33: 142-153.|
|4.||↑||Mao W et al (2007) Clathrate hydrates under pressure. Physics Today 60(1): 42-47.|
|5.||↑||Duarte, CM, Lenton, TM, Wadhams, P & Wassmann, P (2012) Abrupt climate change in the Arctic. Nature Climate Change 2(2): 60-62.|
|6.||↑||Busby J et al (2013) Climate change and insecurity. International Security 37(4): 132-172.|
|7.||↑||Briggs C (2012) Climate security, risk assessment and military planning. International Affairs 88(5): 1049-1064.|
|8.||↑||CNA Military Advisory Board (2007) National Security and the Threat of Climate Change. Alexandria, VA: CNA.|
|9.||↑||Eddy C & Sase E (2015) Implications of the Fukushima nuclear disaster: Man-made hazards, vulnerability factors, and risk to environmental health. Journal of Environmental Health 78(1): 26-32.|
|10.||↑||Schuur E et al (2015) Climate change and the permafrost carbon feedback. Nature 520: 171-179.|
|11.||↑||Phrampus B & Hornbach M (2012) Recent changes to the Gulf Stream causing widespread gas hydrate destabilization. Nature 490: 527-530.|